A female teacher was arrested on suspicion of having a sexual relationship with a student at an all-girls Catholic school in Alhambra, according to authorities.

Alhambra police said 42-year-old Diana Wendel, a teacher at Ramona Convent Secondary School for the past three years, was arrested Wednesday afternoon after a graphic text was found on a student's phone by her relative on Tuesday.

Officials said the student's father reported the text message and turned the cellphone over to police.

"A concerned relative of the female victim actually discovered the sexually graphic text messages and obviously alerted the parent who in turn came to the police department to report this," Sgt. Steven Carr with the Alhambra Police Department said.

Investigators said the sexual contact took place on campus and in the suspect's vehicle. Wendel, who also goes by Diana Yniguez, was the student's math teacher last year, according to officials.

"It appears there was some unlawful sexual contact between the 42-year-old suspect and the 17-year-old minor over the course of perhaps the past two to three months," Carr said.

Detectives said they were concerned that there could be other victims because Wendel, who's been a teacher for 18 years, has taught at a number of schools in the Los Angeles Archdiocese.

The school, which is not part of the Los Angeles Archdiocese, did not have comment when reached out to by Eyewitness News.

Wendel, who was arrested on suspicion of child molestation and contacting a minor for the purpose of committing sex crimes, was out on bail. She was due in court on Friday.